Many cases are known from daily life in which it would be useful and/or desirable to have immediate access to information that goes beyond our personal knowledge and sensory impressions. Examples of this are searching for an electrical cable under the plaster in a wall, navigating in a unfamiliar city, collecting wild mushrooms and inspecting a possibly dangerous object by means of a remote-controlled robot.
The strong dependency of a person having vision on their visual senses clearly contributes to the difficulty of providing additional information. Indeed, the fact that people having vision primarily use their eyes makes it necessary, in many cases, to either input the supplementary information via the eyes or to determine the supplementary information based on the information seen. In the case of input via the eyes, however, the orientation of the eyes must be taken into exact consideration for correct “placement” of the input information and to avoid a “jittering” or “blurring” thereof. In addition, in many cases the information should be made available without a controlled movement of the eyeballs; a car driver may have a map on his lap but would prefer not to have to look away from the street.
Due to their dependency on solid media, e.g. paper, CRT and LCD screens, etc., prior visual information systems have not been in a position to sufficiently fulfill the comfort needs of a person having vision. Non-visual information systems previously lacked the correlation to that which is seen that is natural for people having vision.
DE 196 31 414 A1, whose introduction describes several modern information system, in particular from the military field, contains further information to the prior art.